[wp-hackers] Integrating a form in a page template

Hi all,
I'm trying to integrate a contact form into one of my sites by
creating a page template with the form in it. i set the 'action' to <?
php echo $_SERVER['REQUEST_URI']; ?> and then to <?php echo
get_permalink(); ?> though they both give the same address, except
that the $_SERVER one is relative. anyways, when I submit the form,
(at the same page!) I get a WordPress 404, even though it shows the
permalink of a valid page in the browser, (and if i hit enter, it
takes me to that page)
Please don't try suggesting I use a plugin, I have my reasons for not
using them, mainly the lack of flexibility, and the css block forced
into every page. The code i'm using was tested and is fully
functional on a plain php page.
Anyone know what's going on?